Balanced 3.5 male to balanced 2.5 female adaptor

[handyandyS3]

Hi, I am trying to find a good quality adaptor so that I can use my headphones that have a 3.5mm trrs balanced plug with my Astell & Kern AK300 that has a 2.5mm balanced output socket.
I can find plenty of dubious far eastern adaptors, but I would like something a bit more 'audiophile'.